Small SMB network with outsourced VOIP

Common setup: An SMB has 5 public IPs and outsourced VOIP.

MSP designed the network this way:

Verizon ONT --> Cheap 4-port Netgear switch One switch port --> 1 IP to internal network router One switch port --> 1 IP to externally managed VOIP router 

Is this proper, or is the cheap Netgear switch going to bottleneck it somehow? Is there a more proper setup for an SMB that does not have access to the externally managed VOIP router?